1. Field of the Invention
The present invention relates to a cylinder lock device.
2. Related Art
JP-A-2003-129710 discloses a cylinder lock using pin tumblers. The cylinder lock of JP-A-2003-129710 is formed by housing individual pin tumblers in a plug and a cylinder case. When a genuine unlocking key is inserted into the plug, boundaries of the pin tumblers move to a turning boundary of the plug in accordance with a depth of unlocking code forming recesses formed in the unlocking key, so that the key can be turned in the plug.
However, a discrimination of the key depends exclusively on the depths of the key code forming recesses. In order to increase different locking codes, therefore, what can be done is to increase the kinds of depths of the key code forming recesses or to increase the number of the key code forming recesses. As a result, the cylinder lock, as disclosed in JP-A-2003-129710, cannot be increased the number of different locking codes drastically.
On the other hand, JP-B-07-030641 discloses a cylinder lock, in which tumbler pins in a plug are turned by a predetermined angle on moving center lines by an unlocking key so that the locked/unlocked state is determined according to turning positions. In the cylinder lock of JP-B-07-030641, the tumbler pins are cut into V-shape at their leading ends and are held turnably on longitudinal center lines. The unlocking key is provided with slits, in which the slits to have the leading ends of the tumbler pins fitted therein are arrayed at angles of intersection varied with respect to the longitudinal axis.
When the unlocking key is inserted into the plug, the leading ends of the tumbler pins are so horizontally turned to a predetermined angle as to be fitted in the slits of the unlocking key. In case this state coincides with the set angle, side rods (or side bars) closing the turning boundary with the cylinder case can retract into the plug so that the key can be turned in the plug.
However, the cylinder lock of JP-B-07-030641 is defective in that the unlocking key can be copied merely by tracing the cut angles of the original key.